1. Field
Embodiments of the present invention relate to a control method of an electronic parking brake system, which may reduce noise generated during actuation of an electronic parking brake.
2. Description of the Related Art
Generally, a brake system includes a parking brake, which is normally referred to as a hand brake or a side brake to keep a vehicle stationary. The parking brake is actuated as a driver operates a parking lever provided at one side of a driver's seat within a vehicle. If the driver pulls the parking lever, a cable connected to the parking lever is pulled, serving to keep a rear wheel brake assembly connected to the cable in an operated state. In this way, brake force is generated. On the contrary, the cable is released when the parking lever is released, which releases the brake force.
The above-described actuation of the parking brake using the parking lever requires the driver to directly operate the parking lever. If the driver parks a vehicle without pulling the parking lever by mistake, the vehicle may unintentionally move, e.g., on an incline, causing unexpected accidents. Further, operating the parking lever whenever parking a vehicle or initiating vehicle traveling may make use troublesome.
For this reason, an Electronic Parking Brake (hereinafter referred to as EPB) has been developed to electronically control actuation of the parking brake. The EPB is a system to automatically apply or release the parking brake via a simplified switching operation. Even if the driver does not manually operate the parking brake, the EPB is automatically actuated to keep a vehicle parked or stationary in the case of a vehicle stop or if there is a risk of a vehicle moving backward when started on an incline.
The EPB system provides a variety of functions, such as, for example, automatic coupling of the parking brake upon emergency braking and engine stop, and anti-slip on an incline. Moreover, the EPB system has a Drive Away Release (DAR) function that causes the parking brake to be automatically released if the driver pushes an accelerator pedal in a state in which the parking brake has been applied. In the case in which a vehicle, which is provided with the EPB system having the DAR function, restarts on flat ground or downhill after the parking brake has been applied, the parking brake is automatically released as the accelerator pedal is simply pushed without requiring operation of a separate release button, assisting in conveniently driving the vehicle.
The EPB system may be one of cable puller, motor-on-caliper, and hydraulic parking brake types.
Most vehicular systems are operated via engagement between a motor and a gear and generate noise during operation. In particular, in the case of a luxury vehicle, a greater number of electric parts are mounted, and therefore it is important to reduce noise generated during operation of the electric elements. Moreover, since the EPB system is actuated while the vehicle stops, the driver may feel that the EPB system is noisier than other devices.